1. Field of the Invention
The present invention relates to a front end structure of a vehicle, more particularly to the front end structure of a vehicle body frame equipped with a module carrier.
The present application claims priority from Japanese Patent Application No. 2001-182043, the disclosure of which is incorporated herein by reference for all purposes.
2. Description of the Related Art
Conventionally, a front end of the vehicle body frame is joined to and incorporated into front side members provided on right and left sides of a vehicle body and a front wheel apron by welding. Accordingly, an engine room is formed into a box shape with opening provided on top and bottom sides thereof. For this reason, in an assembly process, an operator is forced to perform the prosess in uncomfortable positions such as looking into the engine room from above or below the vehicle body.
Moreover, if a radiator panel constituting the front end is damaged by a light collision on a front side, it is not possible to replace just only the radiator panel because the front end is formed integrally with the vehicle body frame. As a consequence, work procedures for replacement of components are increased and the number of components for replacement is also increased, whereby too much expense is incurred upon such replacement. In addition, it is not possible to change the radiator panel and components related thereto, which collectively constitute the front end, into lightweight materials such as plastics. Such limitation constitutes obstacles to achieve a weight reduction or a reduction of moment of inertia.
As countermeasures for the foregoing problems, various technologies have been disclosed in the past. According to those technologies, the front end panel is provided separately from the vehicle body frame and the front end panel is detached from the vehicle body frame in the assembly process so as to effectuate the assembly operations from the front of the vehicle body into an engine room. Moreover, assembled components such as a radiator and headlamps are fitted onto the front end panel to form a modularized front end panel. Thereafter, the modularized front end panel is fixed onto the vehicle body frame by bolts or the like.
For example, Japanese Patent Application Laid-Open No. Hei. 7-172345 discloses a technology, in which the front end panel is fixed onto a bumper beam extending in a widthwise direction of the vehicle, and bosses protruding backward from both ends of the bumper beam are fastened to front side members with the bolts, whereby the front end panel is sandwiched and fixed between the bumper beam and a vehicle body frame.
However, according to the prior art described above, the front end panel is just sandwiched and fixed between front end faces of the front side members and the bumper beam. Therefore, if an impact is applied from the front to a lower end of the front end panel, a large bending moment is generated at a portion sandwiched between the front side members and the bumper beam as a pivot. Therefore, the prior art has a problem of weak strength because sufficient resistance against an impact load cannot be obtained.
Incidentally, when the strength is insufficient in the direction of the lower end of the front end panel, if a leg of a pedestrian hits a front bumper, the lower end of the front end panel tends to be inclined backward of the vehicle body due to an impact energy from the leg. If the front end panel is inclined backward of the vehicle body, both upper leg and lower limb(legs) of the pedestrian tend to be bent at a knee joint toward the vehicle body so that the lower limb is caught into a lower part of the vehicle body. Such an aspect is not preferable in terms of pedestrian protection.
In consideration of the foregoing problems, it is an object of the present invention to provide a front end structure of a vehicle including at least a part of a front end panel being modularized as separate components, in which rigidity against an impact load to be applied from a front side of a vehicle body to a lower end of the modularized part is enhanced so as to receive the impact load positively, and the front end structure being capable of protecting a leg of a pedestrian.
To attain the foregoing object, an aspect of the present invention is characterized by the front end structure of the vehicle, in which a module carrier is formed with a carrier upper frame and a carrier lower frame each extending in a widthwise direction of the vehicle and a stay extending in a vertical direction to connect both side ends of the two frames, and the module carrier is fixed onto a front part of a vehicle body frame to constitute at least a part of a front end. Here, the front end structure includes a first fitting face which is provided on the stay, and a second fitting face which is provided on a side closer to a rear end of the vehicle body than the first fitting face, and the both fitting faces are fixed onto the vehicle body frame.
In this structure, the first fitting face provided on the stay which constitutes the module carrier, and the second fitting face positioned closer to the rear end of the vehicle body than the first fitting face are fixed onto the vehicle body frame, whereby a lower part of the module carrier is supported on the vehicle body frame with a truss structure. Accordingly, the module carrier can receive an impact load being applied from the front of the vehicle body to the carrier lower frame.
In another aspect of the present invention, the present invention is characterized by a front bumper beam extending in the widthwise direction of the vehicle and being fastened to the vehicle body frame so as to sandwich the first fitting face together with the vehicle body frame.
In still another aspect of the invention, it is characterized by the front bumper beam being temporarily fitted onto the first fitting face with a temporary fastener, and a pilot pin being provided on a tip of the temporary fastener so as to be engaged into a pilot hole formed on a front portion of the vehicle body frame.
In still another aspect of the present invention, it is characterized by the front bumper beam being temporarily fitted onto the first fitting face with a temporary fastener, a pilot member being formed to protrude from a front edge of the vehicle body frame, and a pilot hole to be engaged with the pilot member being formed on at least any one of the first fitting face and the front bumper beam.
In still further another aspect of the present invention, it is characterized by a front part of the carrier lower frame protruded further forward of the vehicle body than a front part of the carrier upper frame, an upper stage shock absorber being provided on a front face of the front bumper beam, a lower stage shock absorber being provided on a front face of the carrier lower frame, and rigidity in a longitudinal(back-to-front) direction of the lower stage shock absorber being setted higher than the rigidity of the upper stage shock absorber.
In still another aspect of the present invention, it is characterized by auxiliary components of a cooling system being integrated on the module carrier.